Port ccc068d5

Original Commit Message:

    This CL does two things:

    1. It introduces Call/JumpCodeObject as the bottleneck for all calls
       to non-heap-constant Code objects; and
    2. it dispatches directly to the off-heap entry point for all embedded
       code.

    Codegen at runtime remains unchanged to preserve the shorter,
    branch-less calling sequence.

R=jgruber@chromium.org, joransiu@ca.ibm.com, michael_dawson@ca.ibm.com
BUG=
LOG=N

Change-Id: I282a5711fdd481a1fde3569e72f0a6141ebcdf2a
Reviewed-on: https://chromium-review.googlesource.com/c/1396501
Commit-Queue: Junliang Yan <jyan@ca.ibm.com>
Reviewed-by: Joran Siu <joransiu@ca.ibm.com>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58596}